This invention relates to methods of manufacturing tanks with agitation portions. More particularly it relates to a method of manufacturing a seal coating apparatus including a rotationally molded tank with internal paddles for agitation of sealcoat liquid contained therein.
Asphalt is comprised of essentially two components, aggregate and binder. The aggregate is a measured mixture of stone and sand while the binder is a petroleum derivative. The components are combined, heated and blended in a batch plant. The area where asphalt is to be laid is first prepared by grading and compacting the dirt. Gravel is laid on this area and compacted to a thickness of six to ten inches. The hot asphalt mix is then spread over the area and compacted to a uniform thickness of two to four inches.
As soon as new asphalt is laid, the binder begins to evaporate and decay as it is exposed to the damaging effects of the sun (oxidation), rain and snow. Gasoline, oil leaks and chemicals such as road salts can also have a dramatic effect on the life of the binder. As the binder is destroyed by these external factors, its ability to hold the aggregate together diminishes. This problem takes the form of cracks, distortion and disintegration of the asphalt surface. After three to five years under normal conditions, major deterioration has taken place.
Asphalt sealcoat liquid is a viscus brownish liquid that is applied in a thin layer to asphalt surfaces to protect same from deterioration. Sealcoat preserves the elastic and adhesive characteristics of the asphalt binder by sealing out the oxidizing effects of the sun, salts, and deteriorating effects of water and petroleum spillage. Sealcoat also dries to an attractive uniform flat black color creating a like new appearance. Sealcoat can also be mixed with sand to create a non-skid surface with increased wear characteristics. Sealcoat can also reduce loose stone on an asphalt surface. Generally, asphalt sealcoat is a highly economical method of maintaining and extending the life of asphalt surfaces.
The most common asphalt sealcoat is a water base solution of refine coal tar emulsion, gypsum, clay, and silica. Other additives are available to enhance particular characteristics of the sealer such as the adhesion characteristics, drying time, sand suspension, and the color of the sealer. Prior to application of the sealcoat, it is very important to have the asphalt liquid properly mixed and agitated.
Where an asphalt surface being covered is of substantial square footage it is very difficult to manually mix and agitate large quantities of the sealcoat liquid. Commercial applicators include a self-propelled piece of equipment with a hydraulically agitated tank, an associated pumping system for spraying the sealcoat onto the asphalt surface, and a series of squeegees on the machine. As the operator drives the machine forward, the squeegees drag across the surface leaving a thin, evenly applied layer of sealer on the asphalt. This type of equipment is very expensive and is difficult to use in confined areas.
Additionally, trailer mounted sealcoat application systems are known. Such systems include a large tank of two hundred gallons or more installed on the trailer along with ancillary equipment. The fluid in the tank is pumped through a hose and a spray nozzle for spray application of the sealcoat. Supplemental brushing or use of a squeegee may be performed as desired. It is particularly important with these relatively high quantities of sealcoat liquid that the liquid be properly agitated within the tank. Prior art tanks were typically constructed of steel. Also rotary molded tanks are known in which the agitation portion is assembled inside the blow molded drum through the top access opening. This type of assembly is tedious, time consuming, and difficult.
Fasteners such as inserts with threaded bores or the like which may be attached to the rotary mold portions prior to the mold process are known. Such fasteners are typically exposed at the outer surface of the tank after the molding process.